Method and apparatus for applying cover pieces to balls



Jan. 2, 1951 w. E. HUMPHREY 2,536,182

METHOD AND APPARATUS FOR APPLYING COVER PIECES T0 BALLS 2 Sheets-Sheet 1 INVENTOR Filed June 29, 1946 ATTO RN EYE:

Jan. 2, 1951 w. E. HUMPHREY 6,

- METHOD AND APPARATUS FOR APPLYING COVER PIECES TO BALLS Filed June 29, 1946 2 Sheets-Sheet 2 F 5' I IYNVENTOIR 14/4475? 5 yawn/e0 ATTORNEYS Patented Jan. 2, 1951 UNITED OFFICE METHOD APPARATUS FDR APPLYING COVER PIECES TO BALLS H mp ey, ecea e Application J liet-l9; 1946;. SerialNo. 580, 10

23 Claims- 1 ifhis in nti n, ates to a new nd implored method and apparatus for applying. the: outer felt covering pieces about the. vulcanized rubber enter o co oi t nn s al The old manual eth d of aptlyi g h we co e s tions to the core ha be n l ge y s p rseded by the li t hfi li l han p l cat r me od shown applicants prior Patent No. 2,299,544 of October 20, 19412. Briefly described, this mechanical meth cl consistsin p idi g wo o-oall han s W h re opposite y posit ed; ticula ed fl x ble members. made of a um o sec ion which jointly r an appl cato o he s ze and. hape f. t e e-sh ned or Cas n an utli e cha act istic of one section of a ball cover. In each is placed one of the felt covers which has been coated upon what is ultimately its inner surface with a h sive cement which is quite sticky. In order to retain each cover section in, position he hand is surrounded by an. ups anding flang slightly less in height than the thickness of a cover.

The ru b r core or ball enter. which is su stant a y cur d at this m contains. an or gas under a pressure of approximately 17 or 18 lbs. usually obtained by curing the ball with a volatile pill in its center. The core which is also coated with adhesive cement is placed between two of the hands and the hands are the flexed or folded about the core pressing the cover sections in place.

It is one purpose of the present invention to obtain a better adhesion between the cover seo-. tions and the core than has been possible with apparatus and methods of the prior art. Another purpose of the invention is to secure-a closer fit between the edges of the two cover sections. In prior practices the edges of the cover sections. often do not approach as closely as they should so that an excessively wide gap appears around the ball and this gap is apt to be accentuated by the shrinkage of the cover material during the finishing operation when the covered ball is heated for the purpose of curing or setting u the adhesive cement. I

A further object of the invention is to make unnecessary much of the manual labor due to the necessity of tucking down the edges of the cover section after the ball is released by opening the hands. The flanges surrounding the hands are an essential feature of machine covering Joe-.- cause the cover sections are usually somewhat oversize to allow for the subsequent shrinkage and it is, necessary to compress the cover sec? tions somewhat to fit them' within the hands.

he. ndenc of he flanges to P el th eas s oi he cov r s c ions away from the. c re when. the hands are ope d,

It also. an b ec oi the invention to devise n improved appara us or cove ng bal s and; articularly for pplyin cover se tions to t nn s.

ball co e The a paratus i espe f 11y acla d; or ca rying out he PIIOQE ch a o a p rt o thi i vent o With such improved an. paratus and as a pa t thereof is a pro ed mechanical hand. which facilitates the ap- Plioation o he cover section to the core:

B th th me hod and appa a us a e a a le... oi? mo nation. al erati n or m o ement al w ,n. the scope of. the n ention as set io in the appended claims. The invention is illus rat d and de cribed in its several a pec s in i est and prefer ed. form. s th t one skil ed n the artmay n a tioe the same.- While the i vention is pecially designed tor the ap ica ion. i thestancla d fe t. over pi ce or etions to bails, it may have wider a nlioati n.

the drawi gs; F a 1 is a vertic l secti n take thioneh pen boxer chamber whic .v is. employ. d as the pr cess; n his ew it w ll b unde stood hat each hali o th box. supports one the hand ho that he cen al anes at th hands at right an es to ne anot er;

Pier. 2 is a c os ec ion th ough h hamber losed and in n appro ri t pres n this. J he hands a e o clecl bout he core and the col er eot ns are in p ace;

Fig. .3 a -eotion at ri ht ang es to Fis- 2.;

h s, 4 s section. sim lar t Fla u showin he ha ds opened t the end o the cove ing peration;

h" s a secti n at r gh angl s to F 4;;

Fla- 6. is enlarged view tak n a oint along the line. be we n. two hands at the t me he operati n when the ov red ba l s bein trippeo t of he clos d han s. Th lo ation o this new is by the circ e on Fig.- 2;

Fig. 7 is a plan View of one of the hands. re, moved from th ch mber; 1

Fla .8 is on tud nal sect on on theli e i at his. 7- n' th s,v view of the movable hand s ctions raised.

The apparatus cons sts of a chamber which are located two applicators or hands at right angles to one other. The chamber is opened up and the hands flattened and spread out. The operator now inserts a cover piece, coated on its upper face with adhesive, into each hand tucking it within the upstanding flanges. position the upper edges of the cover pieces will bulge over the flanges. This is the condition shown in Fig. 1.

The previously vulcanized core, also coated with the adhesive, is now placed in the center of the hand in the lower box section and the chamber closed which brings the two open hands on opposite sides of the core. This is the condition shown in Figs. 4 and 5 except that the cover pieces are in the position shown by the dotted lines in these views. The chamber is now tightly closed and connection made to a source of pressure and vacuum. For this purpose the chamber may be transferred to any suitable type of press that is provided with connections to pressure and vacuum lines.

Air or other gas under pressure is now introduced into the chamber and the pressure is raised so that it is greater than the internal pressure within the ball core. The degree of pressure may be varied to any desired degree, but whatever the pressure used at this stage it should preponderate appreciably over the pressure within the core so that the core is slightly and uniformly reduced in circumference. While the pressure is maintained at what may be termed super-core pressure, the two hands are flexed and folded about the core so that they completely envelop it as shown in Figs. 2 and 3 and apply the cover pieces about the core.

The preliminary shrinking of the core insures a close flt between the edges of the cover sections and is also a preliminary step which, in conjunction with the next step, promotes a better adhesion between the cover sections and the core.

While the hands are maintained in closed position about the ball, the pressure within the chamber is relieved and a sub-atmospheric pressure is established within the chamber which causes the core to expand and to exert a substantial pressure against the felt covers which are confined by the closed hands. What is now a substantial preponderance of pressure within the core acting against the surfaces of the closed hands forces the core into firm adhesion to the cover. It is obvious that the greater the differential between the pressure within the core and the pressure within the space surrounding the ball, the more compactly will the covers be adhered to the core. While it is not intended to set any exact degree of vacuum to be employed at this time a vacuum of 25 inches has been found to give excellent adhesion between the cover and the core. This sub-atmospheric pressure or sub-core pressure is maintained for an interval suflicient for complete and effective adhesion to take place all about the core. It will be noted at this point that the cracks about the hands are usually sufficient to permit the differential pressures to be effective although the hands are closed, but, of course, the hands may be additionally vented if found necessary or desirable.

,After the requisite interval, the pressure within the chamber is against raised to super-core pressure which causes the core to contract for the second time, and for this purpose a somewhat higher pressure may be used than in the In this first instance. As the core contracts it carries with it the cover sections which now free themselves from the surrounding flanges without any tendency of the flanges to peel back the edges of the cover. This condition and the effect of the super-core pressure while the hands are still closed is illustrated in Fig. 6 where the cover sections are shown as substantially fully stripped out of the flanges. When the hands are opened without contracting the ball, as in previous practices, the flanges often tend to peel the edges of the cover away from the core, but by the procedure which has just been described the cover sections are released from the hands without any tendency of their edges to peel up from the core.

While the high pressure is maintained in the chamber, the hands are opened as shown in Figs. 4 and 5 freeing the ball, the pressure within the chamber is then relieved and the box removed from the press. The chamber is then opened up so that the covered ball may be lifted out of the center of the lower hand.

While it is preferred to use all of the steps which have been recited to obtain the best results, it will be apparent that any one of the steps used singly will achieve at least some improvement over the old practices. Thus, it may be desirable to use only the step of evacuating the surrounding chamber while the hands are closed to obtain better adhesion of core and cover; or it may be desirable to use the high pressure before opening up the hands in order to avoid the objectionable peeling up of the edges of the cover sections without using the other steps. Again, the use of higher pressure to shrink the core before applying the covers will give closer contact of the edges of the cover sections and this may be used without employment of the other steps.

It is, therefore, the intention to cover either the use of all of the steps or any subcombination of the steps or indeed the use of any single one of the novel features of the invention, for each step adds to the efficiency of machine covering.

Having described the steps of the new process, apparatus which is appropriate to the carrying out of the process willnow be described. In the views the two felt cover sections are marked A' and B and the core C.

The chamber or box to which reference has been made is composed of two sections or halves,

which may be of the same size. The lower half of a chamber is indicated by the numeral l and the upper half by the numeral 2. The two sections are hinged together as at 3 so that when thechamber is opened up each section will lie flat on a table. Around the edges of the sections is a gasket 5 which makes a fluid tight seal when the box is closed. While the box may be a permanent part of a press, it is preferred to make it an independent unit so that the cover sections and the core may be located in the box at a diflerent part of the factory from that in which the cover is actually applied to the ball. Any type of press may be employed to hold the box securely closed while the operations set forth are being performed, but to illustrate the operation a lower platen 6 and upper platen l are illustrated. These platens are moved toward and from the box by any suitable means not shown.

They are recessed so as to permit the hand operating mechanism to be actuated either by hand or by any suitable mechanical means which is not illustrated as this forms no part of the present invention.

arca es In order to increase or decrease the pressure within the box and surrounding the ball while the box is closed, a passage I is provided in a wall of the box, preferably in the upper or lid section and the upper platen 7 is provided with a passage H which registers with passage It. The passage H is connected to lines which supply the requisite pressure or vacuum. Any practicable valve mechanism may be used and automatic timing devices may be employed to control the degree of pressure or vacuum and the duration thereof. Devices of this nature are well known in the art of vulcanization and it is unnecessary to illustrate one of them.

In the center of each box section is mounted one of the hands to which reference has been made, it being understood that the central plane of the hands are at right angles to one another. For the purposes of carrying out the process, any type of hand may be employed, that illustrated in my former patent being suitable. However, the invention contemplates a new and improved form of flexible hand or applicator.

In the center of each chamber section is a dowel iii and located on this dowel and held to the bottom of the chamber section by bolts i6 is a two part base indicated as a whole by the numeral 13. The two parts of the base are held in contact by transverse bolts 25 so that they form a solid block, the upper side of which is formed with a central extended portion 2 I the upper face of which is recessed as indicated at 22 in the segment of a spherical surface which forms the central area of the cover receiving surface of the hand. The recess forms the socket or rest in which the core C is placed as shown to the left of Fig. 1.

In the meeting faces of the two base sections are cut out the arcuate channels 24 which are rabbeted as indicated at 25, these channels forming curved guideways for the movable sec tions of the hands. As shown more clearly in Figs. 1 and 8, the radius of each channel 24 is about the center 26 at the extremity of the central area of the hand so that each movable section rocks about this point.

Except that the movable hand sections 28 are right and left they are identical. Each consists of a main body portion, the upper surface of which is recessed in the sperical contour of the outside of the finished ball and is of the proper outline, so that, in conjunction with the part 2| of the base, these elements have the requisite Cassinian or t-shaped outline of a section of the ball cover. The sections 28- are provided with longitudinal slots. Located in the slot in each section and held by pins 38 therein is a tongue or rib 32, the upper surface of which is formed on two arcs which coincide with the curved surface of the movable and stationary hand sections. The tongue 32 is shaped so that it fits and slides within the channel 24-25 in the base 18, as the movable hand section is raised and lowered. At the outer extremities of each tongue 32 is the lug 34 which is connected to the mechanism by which the movable section is rocked in the manner to be described.

Each hand section, whether stationary or rocking is provided with an upstanding flange 35 which projects above the surface of the hand to confine the edges of the cover section. As shown more particularly in Fig. 1 the flange is somewhat less in depth than the thickness of a cover piece so that the latter bulges over the edge of the. flange. When the hand is flexed and closed '6 over the, ball, the flange sections. form 2. continu ous wall about the periphery of the hand. com-- fining the ball cover in place.

This design of mechanical hand is a. substanr tial improvement over previous hands devised for the purpose, for it closes accurately about the ball core.

The means provided for flexing both. handsto and from the. core consists of two pairs of plungers 48, which are reciprocable in packings 4| located in the lids of the chamber. Each pair of plungers is connected to a cross head 42 and between the cross head and the adjacent lid are coil springs 44 which tend to withdraw the hands to their open position. A pivoted link 4'5 connects the end of each plunger to a movable hand section 28. When the box is closed about the ball and located in the press, the plungers are moved inwardly by any suitable operating mech-v anism and are held in that position until the;

cover sections have been firmly adhered tothe core, whereupon they are released and the hands: move to the open. position. The box is then removed from the press and the lid raised so that the covered ball is exposed.

The operation of the plungers is timed in syn. chronism with the application of vacuum and pressure to the interior of the box. It will be:

appreciated that the particular design of themechanicalhand maybe used without necessarily employing the novel method set forth and also that the method is applicable with other types of mechanical hands. While the process is particularly adapted to covering hollow ball cores such as employed in tennis balls, it may be extended to covering sponge rubber ball centers.

What is claimed is:

I. A method of applying adhesive cover pieces to a ball core in which the cover pieces are folded about the core by flexible mechanical hands located within an enclosed chamber, which, process comprises the steps of (1) raising the pressure within the closed chamber above the pressure in the core to reduce the normal diameter of the core before folding the hands about the, core, (2) reducing the pressure within the chamber to a pressure below the pressure within the core while the hands are closed about the core to cause the core to expand against the hands, (,3) raising the pressure within the chamber to a, pointhigher.

than the. pressure within the core to cause the covered core to retract from the closed hands, and (4) opening the hands while the high pressure is. retained in the chamber.

2. A method of applying adhesive cover pieces to a hollow ball core having a superatmospheric. pressure therein by flexible mechanical hands carrying cover pieces and located within a closed chamber, and while the hands are closed about the ball first decreasing the pressure within thechamber below that within the core and then raising the pressure within the chamber above that within the core so as to cause the core to expand and then to contract, and opening the. hands while the high pressure is maintained in the chamber.

3. In a method of applying adhesive cover pieces to an expansible andcontractible ball core by flexible. mechanical hands carrying cover pieces and movable to a position enveloping the core, the steps of reducing thecore below its normal size before the hands envelop the core and, while the hands envelop the core, increasing the core above its normal size, and. then. reducing the core to sub-normal size before opening the hands.

4. A process in accordance with claim 3 in which the variations in the size of the core are obtained by locating the hands in a closed chamher. and by raising or lowering the pressure within the chamber.

5. A method of applying adhesive cover pieces to an expansible and contractible core by flexible mechanical hands, said hands carrying cover pieces held in place by upstanding flanges about the periphery of the hands, said hands being movable to a position enveloping the core, and, while the hands are in enveloping relation to the ball, contracting the core to withdraw the cover pieces from the flanges.

- 6. A method of applying adhesive cover pieces to an expansible and contractible core by flexible mechanical hands located in a closed chamber, said hands carrying cover pieces held in place by upstanding flanges about the periphery of the hands, said hands being movable to a position enveloping the core, and, while the hands are in enveloping relation to the ball, contracting the core by raising the pressure within the chamber to withdraw the cover pieces from the flanges.

7. A method of applying adhesive cover pieces to an expansible core by mechanical flexible hands carrying cover pieces, said hands being movable to a position enveloping the core, and expanding the core while the hands are in enveloping relation to the ball to compress the cover pieces between the core and the hands.

8. A method of applying adhesive cover pieces to an expansible core by mechanical flexible hands carrying cover pieces, said hands being located in a closed chamber and movable to a position enveloping the core, and expanding the core by reducing the pressure within the chamber while the hands are in enveloping relation to the ball to compress the cover pieces between the core and the hands.

9. A method of applying adhesive cover pieces to a contractible core by mechanical flexible hands carrying cover pieces, said hands being movable to a position enveloping the core, said prising the steps of contracting the core by raising the pressure within the chamber and maintaining it in contracted condition While causing the hands to close about the core.

11. A process of applying adhesive cover pieces to an expansible and contractible core in which process flexible mechanical hands carrying the cover pieces move to enveloping position about:

the core, and while the hands are in enveloping relation first expanding the core and then contracting it.

12. The process set forth in claim 11 in which the expansion and contraction of the core is obtained by first lowering and then raising the pressure about the ball.

13. In a process of applying adhesive cover pieces to a contractible core in which process flexible mechanical hands carrying the cover pieces move to enveloping position about the core, 4

the steps of contracting the core while the hands are moving to enveloping relation, and after the cover pieces are applied to the core again contracting the core to release the ball from the hands.

14. The process set forth in claim 13 in which the contraction of the core is obtained by raising the pressure about the ball before and after the cover pieces are attached to the core.

15. An apparatus for covering a tennis ball core having a superatmospheric internal pressure, comprising a closed chamber, a pair of flexible mechanical hands within the chamber which are adapted to close about the core and apply the cover pieces thereto, means to either reduce the pressure within the chamber below the internal core pressure or to raise the pressure within the chamber above the core pressure, and means to flex the hands while the chamber is closed.

16. An apparatus for covering a tennis ball core having superatmospheric internal pressure, comprising a closed chamber, a pair of flexible mechanical hands within the chamber which are adapted to close about the core and apply the cover pieces thereto, means to either reduce the pressure within the chamber below the internal core pressure or to raise the pressure within the chamber above the core pressure, and means extending therough the walls of the chamber and connected to the hands by which the hands may be flexed while the chamber is closed.

17. A flexible mechanical hand for applying a cover section of Cassinian outline to a ball core consisting of a center section, movable sections on either side thereof and arc-shaped guideways in which the movable sections are mounted for rocking movement, and means connected with the movable sections by which they may be rocked to and from closed position about the core.

18. A flexible mechanical hand for applying a cover section of Cassinian outline to a ball core consisting of a center section, movable sections on either side thereof and arc-shaped guideways in which the movable sections are mounted for rocking movement, the said guideways being on a radius the center of which is located at the point on the outer surface of the hand where the two sections meet, and means connected with the movable sections by which they may be rocked to and from closed position about the of the sections jointly form a segment of a:

sphere, and arc-shaped guiding means between the sections, the center of the are being located at the meeting points of the two sections.

21. An articulated hand for applying a cover section of Cassinian outline to a ball core, said hand comprising a stationary section having its outer surface formed as a section of a sphere and two movable sections adjoining either side of the stationary section also having outer surfaces formed as sections of the same sphere, two are-- shaped guideways formed in the stationary section, thecenter of each are being coincident with the abutting surfaces of the stationary section and a movable section, and means carried by the movable sections to engage the guideways.

22. A method of applying adhesive cover pieces to a hollow expansible core while said cover pieces are held by a separable holder in position enveloping the core, the steps of reducing the size of the core by establishing a pressure about the core in excess of that within the core, moving the cover pieces into position enveloping the core, and then establishing a pressure about the core lower than that within the core to cause the core to expand into contact with the cover pieces.

23. A method of applying adhesive cover pieces to a hollow expansible core while said cover pieces are held by a separable holder in position enveloping the core, the steps of reducing the size of the core by establishing a pressure about the core in excess of that within the core,

moving the cover pieces into position envelop- 10 ing'the core, and then establishing a pressure about the core lower than that within the core to cause the core to expand into contact with the cover pieces, and then contracting the core by establishing a pressure thereon lower than around the core to cause the core with the .cover pieces to separate from the holder.

WALTER E. HUMPHREY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,387,305 Roberts Aug. 16, 1921 2,299,544 Humphrey Oct. 20, 1942 2,300,095 Bowers Oct. 2'7, 1942 ,300,096 Bowers Oct. 27, 1942 2,483,234 Roberts Sept. 27, 1949 

